Add webusb notification UI code

components/webusb/BUILD.gn

Index: components/webusb/BUILD.gn
diff --git a/components/webusb/BUILD.gn b/components/webusb/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..e2c78a977476bebf3a7808efdb068adbf44ba7bf
--- /dev/null
+++ b/components/webusb/BUILD.gn
@@ -0,0 +1,23 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+static_library("webusb") {
+  sources = [
+    "webusb_browser_client.cc",
+    "webusb_browser_client.h",
+    "webusb_detector.cc",
+    "webusb_detector.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/strings",
+    "//device/core",
+    "//device/usb",
+    "//ui/base",
+    "//ui/gfx",
+    "//ui/message_center",
+    "//url",
+  ]
+}